Lambertian illumination provides uniform radiance for different angles of observation such that all points of an illuminated area are uniformly illuminated from all directions. True Lambertian uniformity may not be achieved in some practical applications, but devices approaching such uniformity are termed “quasi-Lambertian”. Planar Lambertian (or planar quasi-Lambertian) sources typically emit light of uniform intensity throughout a 180 degree angular dispersion pattern. In certain applications, however, it is desirable to reduce the angular extent of the Lambertian light, such as ship navigational lighting where a beacon needs to be restricted to a well-defined solid angle while retaining uniform brightness with angle (Lambertian) properties, as well as area lighting applications. Coupling light from a plane Lambertian or quasi-Lambertian emitter, such as an LED die, into a more restricted angular distribution can be done using obstructions, but such effectively reduce the energy efficiency of the device by wasting some of the generated light. Moreover, such techniques disrupt the Lambertian property whereby the output light does not exhibit the same uniformity over different viewing angles. Therefore, a need remains for improved techniques by which Lambertian or quasi-Lambertian light can be provided over a controlled dispersion angle.